The quality of meat and fatness of bulls offered ad libitum concentrates, indoors or at pasture

Abstract

The darker coloured meat sometimes reported when cattle finished at pasture are compared to cattle finished indoors may reflect breed, diet, age at slaughter, exercise and/or environment. To determine the contribution of exercise/environment to beef colour, 24, 24-week-old Holstein/Friesian bulls were either housed (H, 2.5 m 2/animal) or maintained at pasture (P, 133 m 2/animal) for 180 days prior to slaughter. The bulls were offered a barley-based concentrate ad libitum and minimum roughage (straw for H and grass for P) to maintain rumen function. Changes in fat deposition were used as an index of exercise. Concentrate intake (group basis) was 7.0 and 6.5 kg dry matter for H and P, respectively. Mean carcass weight was 234 and 246 (sed 4.63) kg for H and P, respectively. Corresponding values for carcass fat score, kidney fat weight and longissimus thoracis (LT) muscle lipid concentration were 3.13 and 2.67 (sed 0.165), 17.9 and 13.9 (sed 2.08) g/kg carcass and 6.7 and 5.4 (sed 0.172) g/kg. Neither LT lightness (Hunter L value) at 2 (mean 35.5) or 7 days (mean 35.7) post-mortem, redness (Hunter a value) at 2 (mean 11.1) or 7 days (mean 13.8) post-mortem nor the pattern of pH fall post-mortem, differed between H and P. It is concluded that exercise/environment sufficient to alter body composition did not affect LT muscle colour in bulls.